A photoelectric conversion device is a device that generates electric charges in a photoelectric conversion layer in accordance with light incident from the side of a transparent electrode having light transmittance of a pair of electrodes, and reads out the generated electric charge as a signal electric charge from the electrode. An imaging device) a photo sensor, a solar cell and the like have been known so far as a device using such a photoelectric conversion device.
For the purpose of improving photoelectric conversion efficiency, Patent Document 1 discloses an imaging device that includes a photoelectric conversion device in which a photoelectric conversion layer containing a p-type semiconductor and an n-type semiconductor is disposed between a pair of electrodes, and a fullerene or a fullerene derivative is contained in the photoelectric conversion layer. However, from the viewpoint of improving color reproduction, an absorbance of the red region (wavelength of 600 nm or more) is required to control the long wavelength end of absorption, but by the method disclosed in the Patent Document 1, it was difficult to manufacture a photoelectric conversion device which controls a long wavelength end.
In addition, Patent Documents 2 and 3 disclose a photoelectric cell in which two kinds of fullerenes are mixed in a photoelectric conversion layer, and further, in order to improve thermal stability, the photoelectric conversion layer is composed of a mixture of substituted and unsubstituted fullerenes. However, in Patent Documents 2 and 3, one of the two kinds of fullerenes is a fullerene having a substituent, and the use of two or more kinds of unsubstituted fullerenes is not disclosed. Further, unlike an imaging device, a photoelectric cell is not required to have an improved color reproduction. Also, in Patent Documents 2 and 3, there is virtually no description about the control of the long wavelength end of absorption in the infrared region, and no specific description or suggestion about the applicability to a photoelectric conversion layer for an imaging device.